1. Field of the Invention
The present invention relates to a pulp washer for washing effluents from a fiber suspension, and, more particularly, to a shower for such a washer.
2. Description of the Related Art
A pulp washer is used to wash effluents from a fiber suspension used in a paper-making machine to make a fiber web such as paper. A fiber suspension with a predetermined basis weight is transported into the washer where effluents in the fiber suspension are typically separated from the fiber suspension through drainage via gravitational force and centrifugal forces. The fiber suspension is normally carried by a wire through the washer. One or more showers which extend across the width of the wire in a direction transverse to the running direction are used to jet a fluid against the fiber suspension which is used to dilute and wash the fiber suspension.
A shower as described above typically includes a pipe with a plurality of holes formed therein through which the cleaning liquid flows. The cleaning liquid is ejected directly from each hole and impinges upon the fiber suspension. Thus, a typical shower ejects a large number of relatively small diameter or fan shaped streams of liquid against the fiber suspension. Separate and discrete streams of jetted liquid may result in mixing and displacement of the fibers within the fiber suspension to an undesirable degree.
Additionally, with a shower as described above, the impingement angle of each jet of cleaning liquid relative to the fiber suspension is predetermined and fixed. However, for different applications and types of fiber suspension, it may be desirable to change the impingement angle between the jets of liquid and the fiber suspension.
What is needed in the art is an effluent shower for a pulp washer which is cheaper and easier to construct, provides a uniform and variable jet which impinges upon the fiber suspension, and allows the jet to impinge upon the fiber suspension at an adjustable angle.
The present invention provides a washer for a fiber suspension with a shower constructed from a pipe with a longitudinally extending slot. A pair of lips are connected to the pipe on opposite sides of the slot and are movable toward and away from each other to adjust a size of the discharge gap defined therebetween.
The invention comprises, in one form thereof, a washer for washing a fiber suspension. The washer includes a porous surface traveling in a running direction and having a width in a direction transverse to the running direction. The porous surface is configured for carrying the fiber suspension thereon. A shower includes a pipe extending parallel to the width of the porous surface. The pipe has a sidewall with a longitudinally extending slot therein. The shower further includes a pair of lips connected to the pipe. The lips are positioned immediately adjacent to and on opposite sides of the slot, thereby defining a slot nozzle with a discharge gap. The lips are movable toward and away from each other to adjust the size of the discharge gap. The pipe may also include a plurality of aligned discharge openings rather than the slot.
An advantage of the present invention is that the basic construction component of the shower is a pipe, thereby making the shower simple and easy to build.
Another advantage is that the slot nozzle is adjustable to define an adjustable discharge gap.
Yet another advantage is that the lips of the slot nozzle may be contoured to provide desired fluid dynamics for a specific application.